The cartons here considered are four-sided containers with bottom, top and lateral sections interlinked by parallel fold lines whereby, in their flattened state, one lateral section is copolanar with the bottom section and is overlain by the top section which in turn is coplanar with the other lateral section overlying the bottom section. During each operating cycle of the packaging machine, an extractor underneath the hopper engages the bottom section of the lowermost carton of the stack with the aid of vertically reciprocable suction means and, in a descending stroke, withdraws that carton from the hopper past an adjacent deflector which engages an adjacent lateral section for erecting same. This motion expands the flattened carton into its unfolded state facilitating an endwise introduction of the goods to be packaged.
In a prior assembly of this sort, the deflector has a stationary ramp lying in the path of descent of an edge of the carton constituted by the fold line linking the adjacent lateral section with the top section thereof. As that edge is being cammed inward by the sloping ramp surface, a position is soon reached in which that lateral section lies flat against the ramp whereupon the zone of contact shifts instantaneously from the upper to the lower part of the ramp, with resulting foreshortening of the moment arm and a change in the angle of attack subjecting the carton to undesirable vertical stress components. This, especially with high-speed operation, may have a damaging effect upon the workpieces.